Emboli capturing device and method of manufacture therefor

ABSTRACT

An intravascular filter device comprising a frame having an open configuration and a closed configuration, the frame comprising a plurality of elongate members each having a proximal end and a distal end, and a proximal region and a distal region and being fixedly connected at the proximal end to each other; and a filter having an open end and a closed end disposed on the frame; wherein the elongate members have a bend distal the proximal region and a helical curve over a substantial length of the distal region when the elongate members are in the open configuration.

This application is a continuation of application Ser. No. 09/972,135 filed on Oct. 5, 2001, now U.S. Pat. No. 6,755,847.

FIELD OF THE INVENTION

This invention relates generally to intravascular medical devices. More particularly it relates to a device used for capturing emboli in a fluid vessel during a variety of intravascular medical procedures and a method of manufacture for that device.

BACKGROUND OF THE INVENTION

There are a number of intravascular procedures where emboli may be created in the vasculature. It may be desirable to capture these emboli before they flow downstream.

SUMMARY OF THE INVENTION

Embodiments of the invention pertain to a device for capturing emboli in fluid flowing in a body vessel lumen and a method of manufacturing the device. Certain embodiments of the invention more particularly pertain to a frame and a filter material portion of the emboli capturing system. In certain embodiments the frame comprises a plurality of proximally fixed elongate members attached to a collar which are expandable into a generally helical pattern. This generally helical pattern of elongate members is configured to open the mouth of the filter to a generally circular shape which contacts the walls of the body vessel lumen to channel the fluid through the filter.

The frame and collar embodiment may be manufactured from a tube of a suitable material such as Nitinol by cutting a number of slits down a substantial portion of the tube and shape setting the elongate members resulting from the slits. This method of manufacture, where the elongate members and the collar are formed from a single tube, provides a ready means of orienting the elongate members with respect to each other and may easily be adapted to frame and filter devices having a different strut configuration.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an isometric view of emboli capturing device 110 in an expanded state according to the invention.

FIG. 2 shows an isometric view of emboli capturing device 110 in a contracted state according to the invention.

FIG. 3 shows an end view of frame 112 used in emboli capturing device 110 according to the invention.

FIG. 4 shows an isometric view of emboli capturing device 210 according to the invention.

FIG. 5 shows an isometric view of frame embodiment 312 according to the invention.

FIG. 6 shows an isometric view of frame embodiment 412 according to the invention.

FIG. 7 shows a tube 114 from which frame 112 may be manufactured.

DETAILED DESCRIPTION

The following description should be read with reference to the drawings wherein like reference numerals indicate like elements throughout the several drawings. The detailed description and drawings represent select embodiments and are not intended to be limiting.

FIG. 1 is an isometric view illustrating an emboli capturing device 110 constructed in accordance with the principles of the invention. A frame 112 includes a plurality of elongate members 116 and a collar 118. The plurality of elongate members 116 is fixedly connected at their proximal ends 120 to each other and may be attached to a collar 118. Plurality of elongate members 116 is configured so that elongate members 116 will bend outward proximal a distal region 130 of elongate members 116 and bend generally helically at distal region 130. Elongate members 116 may also bend generally in a spiral shape proximal distal region 130 of elongate members 116. The elongate members 116 may have a region 132 between the outward bending portion and the generally helical portion whose axis will be generally parallel to the axis running through the center of emboli capturing device 110 both when elongate members 116 are in the expanded position as shown in FIG. 1 and the compressed position as shown in FIG. 2.

A filter material 122 is disposed such that an open end 124 of filter material 122 is proximal a closed end 126 of filter material 122. Plurality of elongate members 116 are attached to filter material 122 at points 128 proximate open end 124 of filter material 122 and extend within filter material 122. Every elongate member 116 may be attached to filter material 122 at points 128 or optionally a lesser number of elongate members 116 may be attached to filter material 122 at points 128. Points 128 are generally located towards the proximal end of distal region 130 and may be located at region 132 to provide an attachment location where filter material 122 is subjected to a minimum of rotational stress.

Emboli capturing device 110 may be disposed on a wire 134 and may be connected to wire 134 at proximal ends 120 of elongate members 116. Filter material 122 may be attached to wire 134 at closed end 126 or may be slideably disposed on wire 134 at closed end 126 of filter material. An atraumatic tip 136 may be attached to the distal end of wire 134.

Emboli capturing device 110 may be compressed within a lumen 138 of a catheter sheath 140 as depicted in FIG. 2. As catheter sheath 140 is slid distally over emboli capturing device 110, a distal lip 142 of catheter sheath 140 forces elongate members 116 inward. As elongate members 116 are forced inward, points 128 proximate open end 124 of filter material 122, which is attached to elongate members 116 at points 128, are forced together, collapsing filter material 122 and allowing it to be drawn into catheter sheath 140. When emboli capturing device 110 is compressed in catheter sheath 140, the plurality of elongate members 116 is disposed longitudinally generally parallel to the axis of catheter sheath 140 and filter material 122 collapses from its expanded shape.

If elongate members 116 have a generally spiral shape bend as described above, when elongate members are collapsing, points 128 will rotate and twist filter material 122 during the collapsing process.

FIG. 3 shows an end view of frame 112 of emboli capturing device 110 in its expanded position. Elongate members 116 have a bend 154 proximal distal region 130 and a generally helical shape 156 at distal region 130 of elongate members 116. When frame 112 is in the expanded position, the plurality of elongate members 116 may be configured so that distal ends 144 of elongate members 116 overlap the adjacent elongate member 116 such that the perimeter of open end 124 of filter material 122 is given a generally circular shape. This configuration allows filter material 122 to efficiently capture the fluid flow.

Elongate members 116 and collar 118 may be made of any resilient flexible material such as Nitinol, stainless steel, polymer or other suitable material. Bends 154 and generally helical shapes 156 may be molded or shape set into the material.

Filter material 116 may be made of a number of materials well known in the art such as polyethylene meshes manufactured by Saati Tech and Tetko, Inc. An appropriate material may allow blood cells to pass freely through while capturing emboli of a targeted size. Filter material 116 is depicted in the drawings as conical, but many shapes which have an open end and a closed end are suitable for use in embodiments of the invention. Filter material 116 may be disposed on Frame 112 such that open end 124 is either proximal or distal closed end 126, as discussed with respect to FIG. 4 below.

Wire 134 may be manufactured from a number of materials commonly used in the art to make guidewires and other wires used in the medical device industry such as stainless steel or Nitinol.

The manufacture of catheters suitable for use as catheter sheath 140 is well known in the art. Catheter sheath 140 may be made from a substantially flexible material such as polyethylene, polymer block amides, nylon, or other suitable material.

Emboli capturing device 110 may be used downstream of a treatment site in the following manner. Emboli capturing device 110 may be inserted into a deployment sheath. Elongate members 116 and filter material 122 may generally be tightly compressed and the deployment sheath may generally be sized to have the minimum outer diameter sufficient to contain emboli capturing device 110. The deployment sheath may then be inserted into a body vessel lumen (not shown), generally percutaneously, and advanced to a location downstream of the treatment site. The deployment sheath may then be withdrawn, allowing elongate members 116 and filter material 122 to reach their expanded state. The treatment site therapy may then be performed. The treatment site therapy may be a variety of intravascular procedures including, for example, balloon angioplasty, stent insertion, or release of a therapeutic agent. If the treatment site therapy creates any emboli, the fluid flowing past the treatment site will flow through the filter material, allowing the emboli capturing device to capture the emboli. When retrieval of the device is desired a retrieval sheath may be distally advanced over the emboli capturing device, collapsing the device as described above. The retrieval sheath may generally have a larger inner diameter that the deployment sheath to accommodate any emboli that may be captured by the device. The retrieval sheath may then be removed proximally from the body vessel lumen together with the emboli capturing device.

FIG. 4 shows an isometric view of an emboli capturing device 210 in accordance with the invention. Like emboli capturing device 110, a frame 212 comprises a plurality of elongate members 216 connected at their proximal ends 220 to each other. Elongate members 216 may also be connected at their proximal ends to a collar 218. Frame 212 may have generally the same shape as frame 112. In emboli capturing device 210 however, filter material 222 is positioned such that open end 224 of filter material 222 is distal closed end 226 of filter material 222. Filter material 222 is attached to elongate members 216 proximate open end 224 of filter material 222 at points 228. Points 228 may be located proximate distal ends 244 of elongate members 216. Filter material 222 may be attached to or slideably disposed on elongate members 216 at closed end 226 of filter material 222.

Emboli capturing device 210 may be disposed on a catheter 246. Other devices such as an angioplasty balloon (not shown) may be attached to catheter 146 or deployed through a lumen 248 of catheter 246. Closed end 226 of filter material 222 may be attached to catheter 246 and collar 218 may be slideably disposed on catheter 246. Emboli capturing device 210 may be deployed and retrieved in a manner similar to that of the first embodiment.

Emboli capturing device 110 may be better adapted for use when the fluid in the body vessel lumen flows distally from the treatment site. Emboli capturing device 110 may be on a guidewire 134 and has open end 124 of filter material 122 proximal closed end 126 of filter material 122. Emboli capturing device 210 may be better adapted for use when the fluid in the body vessel lumen flows proximally from the treatment site. Emboli capturing device 210 may be on a catheter 246 through which guidewires and treatment site devices such as angioplasty balloons may be used, and has open end 224 of filter material 222 distal closed end 226 of filter material 222.

FIG. 5 is an isometric view of a frame 312 according to the invention. Frame 312 may be used with either emboli capturing device 110 or 210. Frame 312 has elongate members 316 connected to each other at proximal end 320 and attached to a collar 318. Collar 318 extends proximally to form a longitudinal catheter like member 352 creating a lumen 350. If frame 312 is used with emboli capturing device 110 in lieu of frame 112, a wire 334 may be extended through lumen 350. Alternatively, member 352 may serve in lieu of proximal portion of wire 334 and one or more elongate members 316 may be made to extend generally parallel to the axis of the emboli capturing device in both the expanded and the contracted state to serve in lieu of the distal portion of wire 334. If frame 312 is used with emboli capturing device 210 in lieu of frame 212, member 352 may serve in place of catheter 240. Frame 312 is suited to manufacturing collar 318 and member 350 from one tube although collar 318 and member 350 may also be made separately and subsequently joined.

FIG. 6 is an end view of an alternate frame 412 shown without filter material. Frame 412 comprises collar 418 and elongate members 416. In this embodiment elongate member 416 have a bend 454 and a second bend 458. This embodiment uses the constraint of a filter material 422 (not shown in this figure) and a vessel lumen wall (not shown) to form a distal region 430 of elongate members 416 into a generally helical shape.

FIG. 7 is an illustration of a tube 114 which may be formed into frame 112 for use in emboli capturing device 110. The material in slots 162 may be removed to form longitudinal members 116 and collar 118. The material in slots 162 may be removed such that slots 162 have radial walls, parallel walls or such that elongate members 116 have parallel walls. The desired configuration may then be shape-set into elongate members 116. Variations are contemplated where different numbers of elongate members 116 are formed and where elongate members 116 have a variety of cross-sectional profiles. This method of manufacture where elongate members 116 and collar 118 are manufactured from a single tube 114 allows precise positioning of elongate members 116. This method of manufacture may easily be adapted for use with many frame configurations, including other frame configurations disclosed herein.

While the invention is susceptible to various modifications, and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that the invention is not to be limited to the particular forms or methods disclosed, but to the contrary, the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the appended claims. 

1. An intravascular filler device for placement on an elongate shaft having a longitudinal axis, the intravascular filter device comprising: a frame having an open configuration and a closed configuration, the frame comprising a plurality of elongate members each having a proximal end and a distal end, and a proximal region and a distal region, the proximal ends of the elongate members disposed around the elongate shaft and being fixedly connected at the proximal end to each other around the elongate shaft; and a filter having an open end and a closed end disposed on the frame; wherein the plurality of elongate members are configured such that the proximal region of the elongate members extends along the longitudinal axis of the elongate shaft; wherein the elongate members have a first bend at a location intermediate the proximal region and the distal region, and a helical curve distal of the first bend and extending over a substantial length of the distal region when the elongate members are in the open configuration; wherein through the first bend of the plurality of elongate members the plurality of elongate members extend laterally outward from the longitudinal axis of the elongate shaft.
 2. The intravascular filter device of claim 1, wherein the elongate members are made from a flexible material.
 3. The intravascular filter device of claim 2, wherein the flexible material is Nitinol.
 4. The intravascular filter device of claim 1, wherein the helical curve in the elongate members is formed into the members.
 5. The intravascular filter device of claim 1, further comprising a second bend distal of the first bend, wherein the helical curve in the elongate members is created by the filter or a vessel lumen constraining the elongate members from fully expanding in the open configuration.
 6. The intravascular filter device of claim 1, wherein the elongate shaft is a wire, and wherein means for attaching the frame to the wire exist proximate the proximal end of the elongate members.
 7. The intravascular filter device of claim 6, further comprising a tip disposed on the distal end of the wire.
 8. The intravascular filter device of claim 7, wherein the tip is a spring tip.
 9. The intravascular filter device of claim 1, wherein the open end of the filter is proximal of the closed end of the filter.
 10. The intravascular filter device of claim 1, wherein the open end of the filter is distal of the closed end of the filter.
 11. The intravascular filter device of claim 1, wherein the elongate shaft is a catheter, and wherein means for disposing the frame on the catheter exist proximate the proximal end of the elongate members.
 12. The intravascular filter device of claim 1, wherein the filter is attached to a plurality of the elongate members proximate the open end of the filter.
 13. The intravascular filter device of claim 1, w-herein the closed end of the filter is attached to the elongate shaft.
 14. The intravascular filter device of claim 1, wherein the closed end of the filter is slideably disposed on the elongate shaft.
 15. The intravascular filter device of claim 1, wherein the proximal end of the elongate members includes means for slideably disposing the frame on the elongate shaft.
 16. The intravascular filter device of claim 1, further comprising a collar fixedly attached to the proximal end of the elongate members.
 17. The intravascular filter device of claim 16, wherein the collar and the elongate members are formed of a single tubular member having an outer diameter and an inner diameter.
 18. The intravascular filter device of claim 17, wherein the inner diameter of the tubular member is between about 0.015 inches and about 0.017 inches; and the outer diameter of the tubular member is between about 0.022 inches and about 0.024 inches.
 19. The intravascular filter device of claim 17, wherein the elongate shaft comprises a catheter wherein the collar and the catheter are formed of a single tubular member.
 20. The intravascular filter device of claim 1, wherein the distal end of an elongate member overlaps the proximal end of an adjacent elongate member when the device is viewed from a distal end view.
 21. An intravascular filter device having a collapsed configuration and an expanded configuration, comprising: an elongate member; a filter having an inlet lumen and a filter wall, the filter disposed on the elongate member; a plurality of struts, each strut having a first portion and a second portion, wherein, in the expanded configuration, the first portions radiate outwards from the elongate member, and the second portions support the filter inlet lumen and extend in a circumferential direction.
 22. The intravascular filter device of claim 21, wherein in the expanded configuration, the second portions cause the filter inlet lumen to assume a substantially circular shape.
 23. The intravascular filter device of claim 21, wherein the second portions are disposed within the filter.
 24. The intravascular fitter device of claim 23, wherein the second portions exert an outward radial force on the filter.
 25. The intravascular filter device of claim 24, wherein each second portion extends over a circumferential section of the filter in the expanded configuration.
 26. The intravascular filter device of claim 25, wherein the plurality of second portions extend around the circumference of the filter in the expanded configuration.
 27. The intravascular filter of claim 21, wherein the second portions have a spiral shape in the expanded configuration. 